Scientists from the Leibniz Institute for Applied Geophysics (LIAG), the Max Planck Institute for Evolutionary Anthropology (MPI-EVA) and other partners have researched the stability and development of landscapes in the Wendland region of Hanover during the past Eemian Interglacial (warm period) around 120,000 years ago. The Eemian is climatically comparable to predictions for the later 21st century. The basic research therefore serves to understand how landscapes respond to climate changes under natural conditions – without additional human influence. As part of their investigations, the researchers also found evidence of the northernmost Neanderthal occupation of the last warm period to date.

Archaeological excavation near Lichtenberg, Germany, in spring 2019 [Credit: David C. Tanner/LIAG]

The "Lichtenberg" project is an experimental laboratory for landscape research: By means of a drilling campaign and with the support of the State Office for Mining, Energy and Geology (LBEG), the research team started a comprehensive investigation of the area near the village of Lichtenberg about three years ago, because the sediments offer a unique insight into the history of the Eemian.

Landscape reconstruction shows the development of a lake in the Wendland region

With the help of borehole geophysics and several seismic measurements as well as the analysis of numerous sediment cores and pollen contents, the researchers managed to reconstruct the development of a small lake as part of a lake landscape that extends over more than 200 square kilometers in the southern Wendland. 

The results of a study now show the course of development: Both at the beginning and towards the end of the Eemian, there was a strong rise in the water level during the climatic changes due to, among other things, lower evaporation caused by more open vegetation, combined with considerable soil erosion causing relatively unstable land surfaces. 

Drilling to investigate the subsurface and further measurements took place about 15 meters south of the archaeological excavations [Credit: David C. Tanner/LIAG]

In contrast, during the main phase of the warm period, closed deciduous forest cover prevailed, which in turn resulted in a gradual lowering of the lake level. The dense vegetation cover of that time provided optimal protection against soil erosion and resulted in remarkable stability of the land surfaces.

"With the help of geophysics, it was possible for us to visualize the landscape not only selectively, but spatially at high resolution," says David Colin Tanner, project manager at LIAG. "Through interdisciplinary collaboration with numerous partners, we were ultimately able to reconstruct the sedimentary, vegetation and hydrological conditions in the course of the Eemian very well -- a great added value also for predicting future landscape changes."

Michael Hein, geographer at MPI-EVA, explains why: "The Eemian interglacial is characterized by similar climatic conditions to those predicted for the course of the 21st century and is therefore highly interesting for basic research. For the Eemian, we can now try to understand how landscapes respond to such climate changes under natural conditions -- without the determining influence of humans.

Evidence of most northern Neanderthal settlement in the last warm period

For the main phase of the Eemian, the researchers found evidence of Neanderthal occupation on the lake shore. According to the current state of research, this is the northernmost evidence of human ancestors during the last warm period in Europe.

Flint tool, found during the drilling [Credit: Max Planck Institute for Evolutionary Anthropology]

Marcel Weiß, archaeologist at the MPI-EVA, adds: "On paper, we now have the northernmost site in Europe from this period, but I have no doubt that the settlement area of the Neanderthals in the Eemian extended even further north. The picture of Neanderthal settlement and migration patterns, as well as their habitat requirements, is still fundamentally incomplete," he said. "Until now, it was mostly assumed that they largely avoided dense forests during the Eemian. This now has to be revised to some extent with the new findings through landscape reconstruction."

Future archaeological investigations will take a closer look at the site where the Neanderthal artifacts were found. Further publications on Neanderthal occupation patterns and adaptation strategies are planned to build on this.

The research is published in Earth Surface Processes and Landforms.

Source: Max-Planck-Gesellschaft [September 17, 2021]